In recent years, the cost of drug development has increased the demands on efficiency in the selection of suitable drug candidates; surrogate end points have emerged to improve this process, hoping that they can help reduce duration and cost of clinical trials. Additionally, they can help in solving ethical issues when measuring the clinical end point involves the application of risky or uncomfortable medical procedures. However, the very mention of surrogate end points has always been controversial, owing in part to unfortunate historical events. As a consequence, there is growing consensus on the use of validated surrogates only. Here, we discuss some of the validation strategies that have recently been proposed and consider the future of surrogate end points in clinical research.
